Machine for producing 3D screen-printed articles

ABSTRACT

The invention relates to a system for producing three-dimensional screen-printed articles, comprising a press bed with a printing screen, by means of which at least one printing exploit can be printed multiple times, wherein after each completed printing, the lift-off can be increased by the application thickness of the previous printing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a continuation of U.S. patent application Ser. No.16/435,325 filed Aug. 19, 2019, which is the continuation of U.S. patentapplication Ser. No. 14/893,235 filed on Nov. 23, 2015, which is a U.S.national phase of International Patent Application No. PCT/EP2014/001383filed May 22, 2014, which in turn claims the priority benefit of GermanyApplication No. 202013004745.3 filed on May 23, 2013, the respectivedisclosure of which are each incorporated herein by reference in theirentireties.

FIELD OF THE INVENTION

The invention relates to a three-dimensional screen printing systemtechnology for producing bodies with a 3-dimensional screen printingmethod, and to the use of the 3-dimensional screen printing system.

BACKGROUND

Introduction

As three-dimensional screen printing processes have become establishedfor the production of molded bodies, a deficiency of available systemtechnologies has developed. At this point in time, there are only twoindependently developed and constructed prototypes of the systemtechnology which have been used to carry out the technical method of3-dimensional screen printing. Without naming the specific system partsand functions necessary for 3-dimensional screen printing, the systemsfundamentally consist of a press bed, flat bed, a four-column liftingunit, and a doctor blade unit. Previous publications on 3D screenprinting methods show these experimental systems without disclosingtheir specific construction, design, and function. Research anddevelopment partners who have necessarily been shown at least individualcomponents and functions of the system technology and function as partof research and development activities are bound by confidentialityagreements. We are not aware of any manufacturer which has implementedthe specific process requirements for 3-dimensional screen printing inan engineered system, aside from our own prototypes developed in-house.As a result, independent third parties at this time cannot use themethod in research, development, or production, based on 3-dimensionalscreen printing processes or 3-dimensional screen printing systemtechnology.

The basis for the engineering standards and construction is the methoddescribed in EP 0627983 A1 for the production of molded bodies with aprespecified pore structure. In this context, a molded body is producedlayer by layer, by a body layer being printed, the layer being cured, anew printing operation being performed on the previous layer, and thencured in turn. For a change in structure, which can be both a change instructure and in material, the screen tool is changed, then printing isresumed in layers. Materials used include ceramic, metal, glass,plastic, and mixtures of the same material groups, or compositemixtures. The 3-dimensional screen printing method itself was mainlydeveloped on the basis of diesel soot particle filters, implants, andabsorbers, including solar heat absorbers, heat exchangers, so-calledflow fields, reactors, and additional functional components. Theabsorber technology possibilities are described in EP 2021594 A1. Themost commonly used materials for the development of the method in thegroup of ceramics are silicon carbide, corundum, aluminum oxide,zirconium oxide, cordierite, phosphate ceramics, and others on toclay-containing ceramics. Development in the glass sector hasconcentrated on the use of recipes containing silicon. Processsuitability in the metal sector was developed using stainless steel,ferrous metals, copper, aluminum, tungsten, molybdenum, and others.Method development using plastics such as acrylates and silicones wasalso successful. The focus of development in this case was methoddevelopment, product development, and most of all possible recipes andprocessability in 3-dimensional screen printing methods.

The necessary systems engineering developments for 3-dimensional screenprinting methods led in our own experimental and application devices forsystems technology to the systems technology, and the system applicationas a 3-dimensional screen printing system and 3-dimensional screenprinting system components on which this invention is based, along withthe use of the developed system technology.

The specifically developed method disclosed in EP 0627983 A1, “Methodfor the production of molded bodies with a prespecified pore structure,”can be listed as the prior art, as well as the use patent EP 2021594 A1,“Device through which a fluid can flow, designed as a solar receiver”,based on the method and likewise from our own development. Additionalpublications on 3-dimensional screen printing methods relate to the3-dimensional screen printing method itself. Photocopies of both of ourown prototypes of the system technology, presented therein, only showrough system images with no technical details or functions of the3-dimensional screen printing, and do not constitute a disclosure of thesystem and functional technology of the 3-dimensional screen printingsystem. In none of the photocopies of system prototypes in thepublications during the method development are solutions shown forsystems and functional technology.

The first and second prototype systems were developed and used in ourown research department.

A number of screen printing systems are known from the literature andhistory of screen printing itself, and these are available on themarket. These definitely do not have the features of a screen printingsystem for 3-dimensional screen printing methods, are not intended forsuch a use, and are also not suitable in the published designs forproducing bodies using a 3-dimensional screen printing method. Offers bysystem manufacturers for customer-specific modifications of hardware andsoftware to specific requirements, said offers kept general in nature,likewise do not constitute a disclosure or prior publication of a3-dimensional screen printing system or the components and functionsthereof.

By definition, the frequently used term ‘object printing’ means printingon an object, but not printing the object itself. An example is printinglettering or a logo on a lighter or pen. In rotary printing, an exampleof object printing is the printing of a cylindrical piston with aprotective glide layer of carbon; an example in a technical applicationis the printing of a seal on a housing part such as an automatictransmission gear selector plate, for example. In such cases, for flatprinting, rotary printing, and other types of printing, an object isalways printed on. The printing itself does not represent the objectitself—as in, for example, the design on a tile. None of the objects orprinting systems named above has a causal connection to a real,3-dimensional screen printing or the system/method technology thereof.

To provide unique assignments of positional indications in the followinginvention, plane parallel surface positions on the plate receiving theprint—also called the press bed—are used in all indications as referenceposition for the vertical height indications on the Z-axis—also calledthe application axis, which is Z=0.000 mm in the starting position. Thisstarting position can also be indicated by the thickness of the mediumbeing printed—by way of example the thickness of the paper which will beprinted, or the height of the component, of an upper housing side beingprinted, of the surface of a lighter being printed, or other objects.The direction of transport of the printed article—the movement directionof the press bed(s)—is indicated on the axes as the x-axis, or theabscissa. The Y-axis needed for positioning, also termed the ordinateaxis, forms a plane parallel surface with the x-axis. The term ‘exploit’does not mean the number of objects in the printing surface of thescreen or template, but rather defines the number of print surfaces of alayout on a press bed.

Problem of the Invention

The invention aims to provide an improved system for the production ofthree-dimensional screen-printed articles.

The problem addressed by the invention is that of a system technologyfor screen printing—or in a special variant, template printing—by meansof which it is possible to produce objects via a 3-dimensional screenprinting method. The solution to the problem addressed by the inventionof a 3-dimensional screen printing system should include both thefunction as a 3-dimensional screen printing system, technical componentsfor the 3-dimensional screen printing system, and the use of the3-dimensional screen printing system itself for the production of bodiesusing a 3-dimensional screen printing method, consisting of the materialgroups including ceramics, metals, glasses, plastics, additional organicand inorganic materials, and biological materials, and mixtures of same.

SUMMARY

The problem addressed by the invention is solved by a system for theproduction of three-dimensional screen-printed articles according toclaim 1.

Preferred embodiments and implementations of the invention are found inthe subject matter of the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a 3-dimensional screen printingsystem in accordance with the disclosure.

FIG. 2 is a printing scheme for an exemplary design with two elongatedpress bed with multiple exploit in accordance with the disclosure.

FIG. 3 is a schematic illustration showing the adjustment positions of ascreen position for plane parallel orientation of the screen to pressbed for a system of the disclosure.

FIG. 4 is a schematic illustration of an adjustment scheme of a doctorblade unit path for a system of the disclosure.

DETAILED DESCRIPTION

The invention relates to a system for the production ofthree-dimensional screen-printed articles—that is, a system whichproduces an object using a screen printing method, wherein athree-dimensional body is constructed by a plurality of printed layers.

The system comprises a press bed with a printing screen.

At least one printing exploit can be printed multiple times by means ofthe printing screen.

The term ‘printing exploit’ is used to mean the surface which is printedby means of the system.

This can often be a bed on which a substrate can be arranged.

According to the invention, after each printing operation, the lift-offis increased by the application thickness of the previous printing.

That is, after each printing operation, the distance of the printingscreen to the substrate and/or to the object is preferably increased,with the effect that the application thickness of the following printingmatches the desired size very precisely.

In one implementation of the invention, the press bed has a plate withmultiple printing exploits.

Due to the use of a plate with multiple printing exploits, it ispossible to greatly increase the speed with which three-dimensionalobjects are provided, by printing multiple printing exploits in oneprinting operation, and therefore constructing multiple objects whichcan have the same or different designs.

The plate can preferably be transported into a curing unit along withthe printing exploits.

In particular, the plate is moved into a curing unit after each printingoperation.

Preferably, multiple plates can be cured simultaneously in the curingunit.

The curing unit can comprise a plurality of receptacles, for example, inorder to simultaneously cure multiple plates.

As such, different plates can be inserted into the printing station inalternation, so that other plates can be printed during the curingtimes.

The system throughput can be significantly increased in this way.

In one implementation of the invention, the system has at least twocuring units and/or curing stations, from which the press bed can befurnished with plates of printing exploits.

These curing stations are preferably arranged adjacent to the printingstation, wherein curing units are arranged on at least two sides of theprinting station, and preferably on four sides of the printing station.

The printing station can therefore be furnished with plates fromdifferent directions.

In addition, the plate preferably comprises a plurality of positioningmarks.

These positioning marks are preferably each functionally assigned to oneprinting exploit.

In particular, due to temperature changes during curing, a change in thesize of the plate can occur.

The size of this change can be detected by means of individuallyassigned position marks, and can be taken into account during thecontrolling of the printing station.

Therefore, according to the invention, in contrast to conventionalscreen printing systems, a screen printing system method technology isclaimed which makes it possible to print multiple print layers on thesame printing object carrier one on top of the other, and in the processto increase the distance from the printing object carrier which receivesthe print for each subsequent printing layer, wherein Z=0.000 mm at thebottom of the screen or the template—also called the printing side—, bythe sum of the application thicknesses H of the printings which werecarried out previously, such that the value A, generally termed thescreen printing plate distance, or also the height, forms a constantdespite the variable total height ΣH from the addition of the individualprint layers, or follow a height adjustment function f(A) available inthe 3-dimensional screen printing. In contrast to the prior art for thesystem design of screen printing systems, in which a height adjustmentis set prior to the start of printing, during the setup phase of thescreen printing system, and this does not change over the entireprocess, with the reference point to the zero position of the press bedconstant at the starting position Z, Z=constant, the height adjustmentchanges with respect to the zero position Z in the 3-dimensional screenprinting system with each printed layer, by the application thickness Hof each printed operation Z=f(H).

According to the invention, in contrast to the prior art, in which onlyone height adjustment is set prior to the start of the productionprocess, during the setup phase, generally by raising or lowering theupper printing mechanism of the printing system then fixing the positionusing mechanical, electromechanical, or electrical devices, or pneumaticclamping devices such as clamping screws, quick clamps, eddy currentbrakes, spring steel clamps, and other braking and locking devices knownto a person skilled in the art, which fix the columns which determinethe lift, following each printing operation for one print layer on oneexploit sequence, according to the design, lowers the press bed(s) tothe printing position by the magnitude of the printing applicationthickness, or lifts the printing screen, the doctor blade, and the floodbar, optionally with the printing unit frame, which is termed the upperprinting mechanism, by the application thickness of the printing. Inthis case, the lifting process can preferably, but not exclusively, bestarted once the flood bar has passed—that is, before the floodingprocess has set in. This is advantageous most of all in cases where oneexploit is printed on a press bed, because the lift modification processinvolves a great deal of positioning time due to the smallspecifications of 0.2 μm to 250 μm per height adjustment change. In theclaimed 3-dimensional screen printing system, in the case of multiplepress beds each having one printing, or one press bed with multipleexploits per press bed, and/or multiple press beds each with multipleexploits, the height adjustment takes place preferably after theprinting of all selected exploit positions.

While height specifications for the printing are known in the prior art,these are not used for the adjustment of the plate height, or even for amodification of the plate height, but rather are carried out for thepurpose of adjusting the color mixture, color intensity, and othersettings related to the quality of the printed image, according to theinvention, in the claimed 3-dimensional screen printing system, theheight specification of the print—in this case the print layer of aprinting operation which builds up the height—is determined in such amanner that the height value is subtracted prior to printing from themeasurement of the height following the printing of the flat layer inorder to obtain the in-process value of the application thickness of theprinting operation just carried out. This height difference value soobtained provides the value of the height adjustment to be carried out.

In the 3-dimensional screen printing method according to EP 0627983,experiments using various materials and layouts during research anddevelopment showed that this height adjustment value ends up between0.0002 mm and 0.2500 mm, according to the grain size and grain shape ofthe material used. Various experiments for the height determinationshowed that it is advantageous to determine each printing operation, andnot to use an average calculated value from multiple printingoperations. This is due to the fact that it was surprisingly shown thatin the 3-dimensional screen printing method, the modification ofparameters by modifying viscosity of the recipe mixture, temperature,the atmosphere in the printing area, the frequency of addition of freshmixture, manually or via a dosing system, and the resulting mixture ofthe already printed mixture and freshly added mixture can specificallychange the individual height buildup of the individual print layers,apart from each other, by up to 25 percent. A further parameter whichinfluences the modification, which is relevant to the applicationthickness, is the transition between the first starting print, in whichthe flood bar is still on the printing substrate, and the free objectprinting in which that flood bar is only on the object itself. Inaddition, the height buildup is subject to a change in the behavior ofthe screen over time and over the printing process. The original screenvalues only settle into a stable operating state over a longer period oftime, such that changes in the application thickness also resulttherefrom.

The measurement itself for the claimed 3-dimensional screen printingsystem is carried out with a measurement contact, but is preferablycontactless. In this case, measurements can be performed in the simplestcase using sensors. However, this requires a measuring time point afterthe curing. Otherwise the print surface can be damaged. This measurementmethod disadvantageously lengthens cycle times in the 3-dimensionalscreen printing system. In the inventive measurement methods for the3-dimensional screen printing system, visual measurements can be used,but require highly-qualified, trained personnel and a longer measurementtime period, and deliver a relative height buildup measurement whichdepends on the individual. The same is true for electrical, gravimetric,or acoustic (ultrasound) measurements, which are nonetheless possible.It has been shown that it is possible to carry out an electronicmeasurement using lasers, laser diodes, and a corresponding analysis,even during the transport process of the object in the system, if thereference position is mechanically stable. In this case, the bestposition of the measuring devices is the height position of the loweredge of the screen holder—especially the bottom-edge position of theprinting screen. This is particularly true because the measurement area,even for objects which are several centimeters high, does not changewith respect to the starting state. If the height measurement in theinventive system technology of the 3-dimensional screen printing systemis carried out during the transport of the object, it is thenadditionally possible—without taking additional measuring time—to eitherprint a measurement part in the layout for the purpose of heightmeasurement, or to produce a measurement series over the object in orderto thereby obtain an analyzable average from a measurement series of aprint layer. This is primarily advantageous if the object has astructure with different material densities which also influence theheight buildup. For flat printing, this value has no significance.However, in the 3-dimensional screen printing method, it is highlyrelevant due to the addition of up to thousands of print layers. This isbecause even a application thickness difference, at, for example, 10,000print layers, would make a difference of 10 mm which need to becompensated for. If one exploit on one or multiple press beds is printedup to multiple exploits on one or multiple press beds, the measurementcan be reduced to one object. However, a continuous measurement of allexploits significantly increases precision. If the object experiencesshrinkage during the printing process, which to date has been avoided byusing special recipes and curing processes, but cannot be completelyruled out, the measurement of the phase which produces the shrinkage theapplication difference with respect to the previous printing operation,which is required for the height adjustment, must be obtained first.This can involve, in unfavorable circumstances, compacting of the objectbelow due to the weight of the object itself, the curing process, or thecooling process. The application thickness, or, rather, the heightdifference with respect to the prior printing, is preferably determinedby more than one measurement position.

In the system technology, the upper printing mechanism of the printingsystem has great importance in the 3-dimensional screen printing method.The construction thereof determines the system components which createshapes. The 3-dimensional screen printing system according to theinvention has a multifunctional upper printing mechanism which is ableto influence various different shaping parameters. One component is thescreen holder, preferably designed as a master frame construction forflat or hanging screens. The screen holder in this case can and must beable to be oriented in all positions, not only to position the screen inthe X- and Y-directions, but also at all corner points of the masterframe and the screen frame holder in the Z-direction, each independentlyof the other. A screen changing device, either by screens inserted fromoutside or by integrated screen positions for alternating screens,should not only enable the printing of a layout in the screen printingsystem according to the invention, but also the printing of differentlayouts and recipes. As an alternative, the printing station can alsoconsist of multiple upper printing mechanism stations. The same appliesto the flood bar unit with the doctor blade and flood bar. This optionenables, in a divided layout, the option of simultaneously printingmultiple materials in one printing screen. During the research anddevelopment phase for the 3-dimensional screen printing method and the3-dimensional screen printing system, it was also noted that thecomplete upper printing mechanism assembly which carries out theprinting can be changed during the buildup of the object for the purposeof changing layout and recipe. This is technically complex, however. Yetin regard to changing time, it requires significantly less process time.Preferably, but not necessarily, the printing screen can be shiftedand/or rotated, and in the process the direction of the movement of theflood bar drive can be, but need not necessarily be, accordinglyinfluenced in such a manner that it is possible to maintain the samemesh direction and printing direction during the printing operation.This is particularly advantageous for maintaining the precision of fitof the underlying printing layer. In one simple design, only theprinting screen position is changed. However, as an alternative, theprinting under the printing screen can be modified, either by modifyingits printed surface or by modifying the position of the entire pressbed.

A further essential method and system component of the 3-dimensionalscreen printing method is the integration of a blower unit into the3-dimensional screen printing system. It has been shown that, incontrast to the prior art in which the printing mixture—ink in thiscase—is applied at a high turnaround rate, in the 3-dimensional screenprinting method it is necessary to influence the atmosphere surroundingthe printing, particularly by the frequently particulate recipecomponents. According to the invention, the use of a gas for the3-dimensional screen printing system is claimed. In the simplest case,the gassing serves the purpose of compensating, by means of a fog, forevaporation of batching water from the recipe mixture on the printingscreen, and simultaneously minimizing drying of the recipe mixture inthe meshes during the time between printing and flooding. In a furtherembodiment, for this purpose the atmosphere is gassed with solvent, aprotective gas, or a reaction gas. If the composition of the recipemixture overall is sensitive to certain gases or moisture, theformulation-conveying components of the 3-dimensional screen printingsystem can also be completely surrounded by the gassing unit, as can bethe transport regions of the press bed exploits and the path to thecuring unit. The space which is to be gassed should either behermetically sealed off against unintended gas flows, or can be operatedwith at least a slight overpressure of the protective or reaction gas.As a further option, the partitioning or the overpressure unit can alsobe used to fulfill certain cleanroom class conditions with respect toparticulate contamination, which is advantageous for electronic objectsor for medicinal objects—for example implants and other bodies. As anadditional option, the overpressure operation or the partitioning, andthe gassing, create the possibility of adjusting a specific moisture andtemperature, including, but not necessarily requiring the water contentand the temperature near the object, either by the gassing medium or bycorresponding cooling and/or heating elements. It has been surprisinglyshown for several experimental printing formulations that theformulation cooled multiple degrees Celsius by evaporation, without theheat of the doctor blade friction, or the desired or undesired heatapplied to the printed article during the curing being able tocompensate for this loss of heat. The associated viscosity change in theprinting formulation therefore had to be taken into account in preparingthe recipe. If the printing formulation has volatile components,overpressure operation and cooling can minimize the emission of thesevolatile components. If flammable substances are used in the printingformulation, all ignition sources in the 3-dimensional screen printingsystem must be constructed accordingly in an explosion-proof design, orignition of the combustible components must be prevented in a protectiveatmosphere. According to the invention, the explosion-proof design mustalso particularly take into account static charges and dischargescreated by material friction.

It is known from EP 0627 983 that, after the printing of a flat layer,the printed layer is strengthened before the subsequent plane isprinted. The strengthening in this case should be performed by chemical,thermal, or physical curing. According to the prior art, drying,cooling, evaporating, or transport passages are certainly known, buteach constitute separate processes and are positioned at the end of theprinting process—normally the application of colour—and constitute anindependent, self-contained process related to one-dimensional printing.

In the 3-dimensional screen printing system according to the invention,the curing, which is embodied conventionally in its function as a dryingunit, is a component of the printing process. This is because thepreparation of the object for the subsequent height-building printingstep is carried out in the process. If a press bed with one or moreexploits is used, the curing unit can be positioned on one side thereof.If two press beds with one or two sides are used, the press beds are fedfrom up to four directions of the printing station; up to four curingunit positions are solutions in the arrangement of the curing unitcomponents. In this case, in the 3-dimensional screen printing systemaccording to the invention, all exploits of one press bed are printedone after the other, and then subsequently cured at the same time. Theresulting shortening of the system size and the time required for thecuring per exploit is utilized according to the invention for theclaimed 3-dimensional screen printing system. Likewise, the possibilityof changing or combining the source which achieves the curing 13 forexample but not exclusively electrical light sources and/or heatemitters, fog or spraying devices, is a design element of the3-dimensional screen printing system according to the invention.

The illustration in FIG. 1 illustrates and claims, as an example for aplurality of 3-dimensional screen printing system designs, a systemsketch which serves the purpose of explaining the primary components ofthe system and the function of the system. In this illustration, No. 1is the upper printing mechanism of the 3-dimensional screen printingsystem, No. 2 is the station which preferably contains not only driveand positioning elements but also the important system control elements.No. 3 is a press bed—in this case an elongated press bed with multipleexploits. No. 4 is a second press bed, likewise with multiple exploits.No. 5 depicts the curing unit for the first press bed. No. 6 depicts thesecond curing unit for the second press bed.

In the embodiment, printing is carried out at a right angle, in the Ydirection, to the bed transport direction X. In the 3-dimensional screenprinting system presented by way of example, the position of the pressbed 1 is printed for 10 exploit copies. This is then transported underthe first curing unit No. 5 in which the first ten exploits are cured.During the exit of press bed 1 from the printing station, the secondpress bed is transported into the printing station, where ten exploitsare likewise printed directly one after the other onto the press bed.While the second press bed travels out of the printing station under thesecond curing unit No. 6 to be cured, the upper printing mechanism ofthe 3-dimensional screen printing system is lifted to a degreecorresponding to the print application thickness measured value whichwas performed on press bed 1 in the meantime. In a constant alternation,press bed 1 travels again into the printing station, then into the firstcuring unit, press bed 2 travels into the printing station, and fromthere under the second curing unit, and so forth.

The printing scheme for the exemplary design with two elongated pressbed with multiple exploit is illustrated in FIG. 2 . In this case,according to the invention, printing is performed orthogonally—that is,in the Y direction—to the bed transport direction X, because in this wayit is possible to minimize the distance ΔX between the exploit copies,such that it is possible to accommodate a maximum number of exploits perpress bed. In a simplified design, the 3-dimensional screen printingsystem is equipped with a press bed for the purpose of producingobjects, as illustrated in FIG. 1 with two press beds, or also, usingthe same type of transport, up to 8 or more press beds and curingunits—comparable to pieces of a pie with the printing station in thecenter thereof. If there are more than 2 press beds, the printingstation, and/or the upper printing mechanism, and/or the printing screenand the doctor blade and flood bar drive, can be rotated according tothe station arrangement of the printing transport direction X by thesame degree in order to enable the orthogonal printing direction withminimal distance ΔX between the exploits. ΔX is the sum, right and left,of the blade overlap to the layout, which is less than the sum of theblade infeed and outfeed path. If a long press bed is used, by way ofexample, the number of possible exploits grows with a smaller layout inthe printing screen—in the worst case, with one object in the layoutsurface of the printing screen, the number of the objects which can befed together to the curing in one work step.

If one or more further materials are printed according to the design,for example in the case of multi-layer material objects, this can beperformed by one of more further centrally arranged printing presses, oralso by further printing stations which follow upon one another in thenegative press bed transport direction −X. The alternative embodimentsof the press bed as a round bed, either as a semicircle circle segmentor a closed circle with one press bed or multiple press beds connectedin series, is obvious in this case for the design of a 3-dimensionalscreen printing system.

Such a system constitution of the 3-dimensional screen printing systemreduces cycle times to a significant degree, in the present batchoperation with long pause times for the printing in the screen printingsystem, compared to conventional screen printing technology in whichproduction proceeds in a line—that is, with a short pause of the partbeing printed in the printing system. The long single cycle times resultfrom the necessity of stabilizing the individually printed print layerin the 3-dimensional screen printing method prior to the following printlayer, such that the following printing can bind to the printing below,on the one hand, and on the other hand the already printed elementconsisting of more than one print layer is not deformed by the pressingforce of the following print layer, or the weight thereof which isformed overall.

Corresponding to the inventive thinking, the 3-dimensional screenprinting system has a plurality of method-specific constructions anddesign details which enable a standardized 3-dimensional screen printingof a body.

According to the invention, it was possible to realize, as an essentialcore component for the 3-dimensional screen printing system, that thelift unit for the upper printing mechanism, and/or the lowering unit forthe press bed, must have special properties compared to conventionalscreen printing systems for one-dimensional screen printing.

The first relevant group of the 3-dimensional screen printing system tobe mentioned is the system component by means of which is possible tomeasure, set, and control the lift-off.

It has been discovered that it is essential that, for the lifting of theupper printing mechanism, a central lift device can be used—such as aservomotor or step motor with a chain or belt drive, but there must be apossibility of correction on all lifting axes in order to compensate forthe variable component expansion which occurs over the lifetime of thesystem. In the simplest case, this an integrated belt or chain tensionerwhich compensates for the differences in expansion by means ofmechanical or electronic control. In this case, such a device can alsobe controlled by measuring devices attached to the lift unit or upperprinting mechanism. This embodiment of a lift unit for the upperprinting mechanism provides quite good results for simple printing ofobjects in the 3-dimensional screen printing method, but not for fineand high-precision print layer thickness applications.

A second embodiment of the lift unit of the upper printing mechanism for3-dimensional screen printing systems is a non-central drive of at leasttwo lift unit axes at the same time—preferably one at the print infeedand one at the outfeed, likewise controlled and compensated for mimickedchanges.

In the third embodiment of the lift unit of the upper printing mechanismfor 3-dimensional screen printing systems, there is a decentral drive ofall lift unit axes of the upper printing mechanism at the same time,preferably one on each corner of the upper printing mechanism, whereinthe position of each lifting axis is monitored using sensors and can becontrolled.

For each embodiment of the lift unit of the upper printing mechanism for3-dimensional screen printing systems, it has been shown that positionfixing of the lift columns is necessary with increasing structuralfineness of the object. Likewise for increasing quality, this a simplemotor brake for the central drive, a motor brake on the two and/or fourdrive devices, followed by a clamping fixation of the lift columnsagainst the system frame. However, the highest precision in a3-dimensional screen printing system is achieved by a fixed support oneach lift column axis. This fixed support according to the invention isa support on which the upper printing mechanism is lowered by the liftdrive. In this case, the support according to the invention cansimultaneously take over the function of height adjustment by changingthe position of the support surface more or less for the liftadjustment. The functional advantage is a fixed stop in each position ofthe upper printing mechanism, with the possibility of changing theposition of the same in dimensions of 0.0002 mm.

According to the invention, it has been shown that uncoupling the weightof the lift unit drive is advantageous for the precision of reproducingthe positioning. This can be performed in such a manner that acounterweight is opposed during the height adjustment to the weight ofthe upper printing mechanism. This counterweight can be generated bysimple pressure cylinders which are adjusted to the weight of the upperprinting mechanism at each of the corners of the upper printingmechanism—for example using compressed air, hydraulics, or electronics.Forming of a counterweight using a weight mass is possible, but overallnegatively impacts the weight of the upper printing mechanism. Thecounterpressure devices according to the invention simplify thebalancing out of the load on the lifting axes, and significantlyincrease the reliability of the positioning. If a fixed stop is alsoused for the position adjustment, this then according to the inventioncounteracts the change in the lift axes load, and the associatedposition change due to natural material expansion and bending due tostatic and dynamic load changes.

The increasingly highest precision according to the invention in thelift positioning and the stability of the position during the printingprocess—in this case most important the flooding step and themeasurement of the printing application thickness—is performed inincreasing order by a drive brake and/or lift column clamping and/orcounterpressure device and/or fixed support and/or an additionalseparation of the lift axis and the guide axis. It has been shown thatthe stability of the upper printing mechanism resulting from the use ofadditional guide columns not only has a positive effect on thereliability of the position with respect to the lift-off, but also onthe dimensional stability of the printed image positioning. As such,according to the invention, the possible, optional attachment ofseparate guide columns with no lift function, according to the requiredpositioning precision, is claimed. If the guide column according to theinvention is used to guide the lifting or lowering of the print upperprinting mechanism, the lift drive construction can be given a minimizeddesign if the counterpressure elements are used at the same time, and ifa fixed support is used to fix the position of the superframe. Incontrast to the simple reduction of weight of the upper printingmechanism up to weightlessness of all axes at 0 kilograms—floating—oneach lifting axis, to the unloaded fixed support adjustment, which canthen even be carried out using the smallest, low-power motors, in thelift-off adjustment according to the invention, a moderate load shouldremain on the lift device in order to minimize position changesresulting from load increases in the bearings. In the development of theinvention of the 3-dimensional screen printing system, it has been shownthat, without a stabilizing measure being implemented, not only couldthe static positioning precision be significantly improved, but also thedynamic weight change caused by the flood bar pressure and the flood barbeam weight shift along the bar path can be compensated with adisplacement of the balance point of the upper printing mechanism in theX direction. In simple, two-dimensional printing, this factor isessentially meaningless, but is significant in 3-dimensional screenprinting method due to the plurality of print layers and the summationof errors.

Under the same equipment features, the position change of the lift-offcan also be performed by lowering the press beds. Although the functionhas the same precision results and can be carried out, it should beconsidered disadvantageous from a structural point of view thatincreasing press bed size and exploit length of the press bed results inincreasing system component size which needs to be positioned. Inaddition, the positioning of the guides of the press bed and the beddrive thereof, for positioning travel paths up to more than 10 meters,is substantially more susceptible to faulty positioning. The positioningof the lift-off inside of the accordingly fixed upper printing mechanismis likewise possible. In this case, it is only necessary to position thescreen holder and the flood bar unit with its guides. However, for alift change via the screen and printing unit, it is no longer simple tohouse the required lift equipment. It is functionally feasible in theconstruction of the 3-dimensional screen printing system, but isdifficult in actual construction, with the exception of severalspecialized applications.

The second relevant group of the 3-dimensional screen printing system tobe mentioned is the system component by means of which is possible totransport, print, and cure the object in the 3-dimensional screenprinting system.

In contrast to the prior art, in 2-dimensional screen printing, thepress bed(s) are subject to a long pause time in the printing system,and are subjected to a cyclical alternation of operating conditions as aresult of the curing integrated into the printing system. The press bedposition also differs due to the possibility of multiple exploit on thepress bed. It has been shown that conventional press beds tend to deformunder long-term vacuum load, and demonstrate concave deformation. Inaddition, the bed dimension proceeding from the bed stop, and/orproceeding from the bed drive position anchoring, changes over thecourse of long-term use. While the deformation leads to uneven flood barpressure and the impression of the individual print layers of the objectassumes different heights, the bed expansion results in a relativelayout shift over the print layers. Because the heat created during thecuring, adding a cyclical load, leads to a delocalization of the printedimage—simply put, to tilted object walls out of the in-plumb Y axis—thestability of the object also suffers due to the resulting overlap of theprint layers. In particular, the aspect of multiple exploits on onepress bed has led to the solution of the problems of conventional pressbeds in the use thereof for 3-dimensional screen printing. Because ithas been shown that it is possible to fix the print substrate to thepress bed by means of a low vacuum, using very low quantities of power,the press bed is preferably equipped with a small vacuum volume. Thebest results were achieved with double plates which have vacuum-guidinggrooves on both sides. Then the vacuum bores acting on the printsubstrate are inserted into the point of intersection of the vacuumgrooves. In general, any press bed construction designed for a long-termvacuum can be used for the 3-dimensional screen printing system. For thepurpose of compensating the long-term vacuum deformation, in a classicpress bed construction with a high vacuum chamber volume on theunderside of the bed, a combination of compensation bores—for exampleequipped with automatic valves—the loss of vacuum on the upper side ofthe bed because of the print substrate can be compensated so that thetendency to curve is suppressed. However, in this case, the requiredvacuum power of the vacuum generating assembly must be taken intoaccount. In any case, in a 3-dimensional screen printing system, thenegative effect of the classically used lateral channel compressors withrespect to transmitting vibration to the actual printing system,emitting noise, and most of all producing heat should be avoided in 100%switched-on long-term operation, preferably by the use of quiet,oil-free membrane pumps or oil-free rotary vane pumps which preferablyshould be arranged outside of the printing station—for exampleunderneath the curing units.

The second press bed aspect is the positional stability of the press bedin the X direction for each exploit of the print(s). While in classicalscreen printing the known press bed positioning is absolutelysufficient, this not the case for 3-dimensional screen printing.Although the known advancement methods using controlled travel detectionare adequately precise for very simple objects and single-exploitprinting, they are not for finely structured object, or in multi-exploitprinting. According to the invention, it has been shown that the pressbed can be driven pneumatically, hydraulically, electrically, ormechanically, either from two sides or centrally at the center point ofthe Y axis of the press bed—but preferably when the press bed travelsinto the printing station at the start of the press bed. A drivearrangement in the classical center of the X axis of the press bed ispossible, but leads to the exertion of pushing and pulling tension anddifferent loads on bed bearings, with resulting positioning imprecision.Because a large, and in the present embodiment long, press bed isequipped with a plurality of printing positions which additionally canalso be variably adjusted, the positioning of the press bed in the Xdimension must preferably, but not exclusively, be arranged in thelayout center of the printing of the printing object being carried out.The absolute positioning and position fixing should be arranged in thelayout center of the exploit, and be designed to act on both sides inorder to prevent press bed shifts in the Y axis direction. Designed inthis way, the heat expansion of the press bed emanating from the layoutcenter at each layout point independently of each other only affects thepositioning precision, even if overall, by way of example for twentyprinting exploits on a press bed, the heat expansion increases twentytime from one end of the press bed to the other, the effective heatexpansion for each individual exploit is only a factor of 1. For finepositioning and bed fixing during the printing process, parallel clamps,pneumatic or hydraulic cylinders, magnetic holders, conical, pyramidalcentering, or trapezoidal fixing devices, or similarly working elements,and/or axis clamp devices, are preferably suitable, but not exclusively.The fixing devices must be shared so that they push, compress, pull,allow the gliding of, or attract the press bed to the prespecifiedposition in the middle of the respective print layout. The positioningvia an end stop with a fixed element, preferably in the geometric centerof the printing screen above the same, and one or more stopcounterpressure elements according to the number of the printingexploits, with or without dampers, working on each enter point of theexploit layout center points, is/are also a solution for finepositioning of the bed for the 3-dimensional screen printing system—withthe requisite that the print layout is arranged centrally in the screen.The important advantage of a mechanical positioning and fixing of thepress bed is the elimination of complex measured value determinations,evaluations, and calculations for the bed positioning via the bed drivesystem, because the layout center point remains the center point underall operation conditions. As such, a motor drive with incrementallydetected values can certainly approach a position of a bed precisely,although for increasing drive weight with proximity controls which takelonger, but cannot hold said position constant over variable operatingconditions, most of all temperature and weight. In addition, a chain,belt, shaft, piston, or sliding drive is suitable only for one press bedposition under the variable operating parameters. In contrast, a pairingof conventionally controlled drive technology—for example via an Omegabelt drive arranged centrally in the Y axis direction of the bed, whichaccording to the invention constitutes the optimum drive type for3-dimensional screen printing systems, approaching multiple positions ofthe press bed is possible if a fine positioning is carried out in eachprinting exploit center point via a fixing element. With the use of adrive with a stop point, a 3-dimensional screen printing is possible,but in this case it is necessary to determine, with great effort thedimensioning change of the press bed depending on position, and topermanently correct the control position for the press bed. Because thechange parameters of belts, chains, shafts, spindles and axis generallyadditionally are incorporated into the control position calculation,this is only possible as a solution for the 3-dimensional screenprinting system, for positionings loaded with the summation of possibleerrors, when precision requirements are lower.

For three-dimensional screen printing of objects on a three-dimensionalscreen printing system, it is necessary to implement the process ofcuring and/or drying in the printing system. Whereas with conventionalscreen printing techniques, the drying of the print takes place inaccordance with the prior art on separately attachable systems, which donot directly engage in the printing process of the screen printingsystem and are usually operated continuously, in the 3-dimensionalscreen printing system for the production of objects according to the3-dimensional screen printing process this must be controlled by thestay of the print objects in the screen printing system for an extendedperiod of time and according to a plurality of printing and curingoperations on the building object, as well as the need for long-termfixation of the printing substrate of the object to maintain positionalstability during the entire print time; curing as well as warming of theobject arising from temperature effects, with the print object carrierand the press bed located beneath, while minimizing the heat load of thedrive and guide elements under the press bed or beds, thus allowingmaximization of cycle times. Allowing for environmental considerationsand for minimizing the required footprint of the 3-dimensional printingsystem, as well as taking into account the changing material propertiesof the formula within the building printed object, the functioning ofthe curing system or systems in particular but not exclusively for themultiple exploit of one or more press beds with an occupancy of thepress bed with at least one printing exploit up to a layoutsize-dependent maximum number of exploits of a press bed, consists ofthe individual functions: Curing process with or without the addition orremoval of media such as air, gas, humidity, reagents, vapors, dusts,mists, or drops, preferably finely and homogeneously distributed in eachcase. The curing process itself is controlled by time and/or temperatureand/or quantity, wherein the nature of the mode of action of curing canchange over the period of curing. Curing takes place at least in thepress bed surface covered by exploits and should not change in theirsurface dimensioning during the time of the entire object production.The curing system has the capacity to direct the action of curing, forexample, the direction of radiation of an IR or UV lamp from the same ordifferent directions onto the building object. If heat or vapors arisefrom the curing process, a device is to provide for suctioning them off,but suctioning preferably is not solely upward, so as to minimize aninhomogenizing effect from currents arising on the object surface or instructured objects inside the structures. In most cases, the curingprocess is accompanied by heat development, if this is not the curingeffect itself. The curing system(s) of the 3-dimensional printing systemis also equipped with a heat dissipating device such that uponcompletion of the time of curing effects, the atmosphere located abovethe object, preferably but not exclusively air with more or less gasleaving the object, rising heat and/or moisture in the form of water orsolvents or volatile components of the formulation of the mixture withwhich the object has been printed, or a composition thereof, whereinthis may also be a previously supplied curing agent, is discharged.Tempering of the object to a previously determined and fixed temperatureis also associated with the discharge.

The distance between the object and the curing element must be viewed asessential for curing. This distance is crucial for the effect,intensity, duration, and duty cycle of the curing device. Experimentshave determined that it is not necessary to raise the curing system inthe narrow limit of the printing height change, but this can be done atintervals in the millimeter range.

If the lift-off change is made by lowering the whole press bed, there isno need for an additional change in position of the curing system, sincethe distance of the curing element to the object surface then does notchange. If the lift-off change is made, however, by means of the upperprinting mechanism or the printing mechanism with screen holder, thecuring system must be adjusted in distance within predeterminedintervals by the height of the printing object or objects. In somecases, the curing requirement must be met as a function of time and/oras a function of object height, because the absorption properties of theobject can change with increasing object height. The distance betweenthe printing object top and curing element is corrected in time and/ordistance and/or intensity. Curing system height adjustment iscomfortable if it coupled directly to the upper printing stationmechanism and raised in parallel with this. On the other hand, theadditional weight load on the upper printing station mechanism from thecuring system coupling affects the positioning accuracy of the lift-offadjustment significantly, so that this solution should be used only forcoarser objects and less sensitive printing mixture formulas.

If the press bed is not in the curing process, the curing system or itscuring elements must be switched off if possible, above all in orderavoid unnecessary burdening loads on the underlying system equipment; inaddition this operating mode significantly increases the energyefficiency of the entire 3-dimensional printing system, which isdifferent from conventional curing or drying systems for conventionalprinting, which are operated continuously as a rule.

Through the simultaneity of curing and if necessary cooling of all theexploits of a press bed at the same time, the required time for them isexpended only once, so that time expenditure required for a whole cycleof a press bed with a plurality of exploits can be greatly reduced incomparison with, in the unfavorable case, a press bed covered with oneexploit. For example, in the single cycle of a press bed with oneexploit, if the print time is say 1.2 seconds, the curing time 45seconds, and the cooling time 35 seconds, taken together with the timerequirement of bed transport of likewise 1 second, more than 82.2seconds will be required for a print layer for one exploit. The timerequirement for the height adjustment of around 11 seconds isimplemented within the curing time, so that no additional time isrequired. If the time is determined for a 20-copy exploit, this givesfor the printing of 20 times 1.2 seconds=24 seconds, for the curing 1times 45 seconds, for the cooling 1 times 35 seconds, for the transport20 times 1 second within the printing station and 1 second for thetransport from the printing station under the heating device. For the20-copy exploit then in total a time of 125 seconds is required. For 1exploit therefore for example 6.25 seconds.

Since already during the curing of the first press bed, the second pressbed can be printed with exploits, the 3-dimensional printing system hasno downtime. For a 20-copy exploit then the effective process time of aprinted layer is 6.25 seconds, as an example. With the time reductionfrom the example, two significant parameters arise with a press bed withmultiple exploits:

The production time of the 3-dimensional printing system, for example,is reduced to 7.7% compared to the single exploit of prototypes with aprinting exploit of a press bed and a curing system, which correspondsto an increase in unit capacity by a factor of 13.

When using two press beds, the factor is further improved in that, basedon the example, the second press bed is printed immediately after thefirst press bed, while first press bed curing takes place, and thus theeffective time for an exploit drops to 3.35 seconds.

Required times for mass proportioning, lift-off change, etc. occurwithin the section overlaps, so that no additional time is needed. Theeffectiveness of the 3-dimensional printing system is determined in itstime requirements mainly by the curing time and the exploit quantity. Areduction to less than 4% of the effective cycle time of a 3-dimensionalprinting system compared with the existing prototype systems in singleprint with one press bed and one exploit graphically illustrates theeffectiveness of the 3-dimensional printing system technology made andclaimed with the invention.

The reduction of the cycle time already occurs with two press beds withone or two curing systems and one exploit per print table, or even withone press bed with more than one exploit. In this special case, thesecond exploit can also be a second medium which is consecutivelyprinted in the printing station, which is then equipped with two screensand two doctor blades.

The calculation example cited is determined for a material withcombination curing by heat/radiation with high heat storage capacity,high reflectance in the grain, and porosity of almost 50% by volume.

The third essential component group of a 3-dimensional screen printingsystem is the upper print mechanism that performs the printing, withprinting mechanism frame, doctor blade unit drive, and doctor blade unitmechanism with integrated measuring devices and controls. Contrary toconventional screen printing systems for flat printing, the function andsetup of the upper printing mechanism with screen holder, screenpositioning, and printing mechanism is of crucial importance for thefunctionality of the 3-dimensional screen printing. Contrary to priorart in the classic graphical and technical screen printing, an errorresulting from the upper printing mechanism in 3-dimensional screenprinting is summed up with every printing layer of the object. As errorsummations on the object surface arise waves, unequal heightdistribution, areas with more or less printout, and open defects withoutmaterial application areas. In particular, in 3-dimensional screenprinting processes on an 3-dimensional screen printing system it is notpossible to test the settings and continuations by so-called proofs. Onthe contrary, in the 3-dimensional screen printing method, it is acompulsory requirement that the first printing and all subsequentprintings, even after screen cleaning, mixture change, layout change,material change, or print interruption, in positioning, print imagehomogeneity, print job thickness and layout alignment with theunderlying print layer, are perfectly formed without proof. A faultyfirst print or a faulty print in one of the following print layersinevitably leads to failure of the exploit and thus of the object, evenif, for example, out of four thousand print layers only another 20 printlayers, for example, are to be printed.

This necessary printing perfection, which can also be used as animprovement in conventional screen printing systems for classic screenprinting, is achieved by the special design of the screen holder, of thepositioning system, of the doctor blade unit drive, of the doctor bladeunit, and of the structure of the upper printing mechanism.

The screen holder of a 3-dimensional screen printing system must bedesigned for a flat screen and for a round screen with an overlying aswell as a hanging screen as a statically stable structure. In particularthe application surfaces for the screen edge in the screen holder mustbe designed as a plane parallel rail, which does not warp with an unevenscreen frame shape, or thickness differences in adhesive and screenmesh, or screen frame warping, even under the effects of screenclamping. The compensating resilience of the screen holder appliedaccording to the prior art results in an uncontrollable delocalizationof the screen mesh horizontal position to the X-Y direction and to achange in the screen tension. But since no screen is like another, bothin frame and in mesh, and thus constitutes the greatest error sourcegenerally for 3-dimensional screen printing and the 3-dimensional screenprinting system, arising due to uneven adhesive application, framestrength differences, frame warping, mesh warping, an intensetemperature and moisture dependency and constant screen parameter changeover the screen history. In order to align a printing screen planeparallel to the press bed surface in a 3-dimensional screen printingsystem, it has proven advantageous for the 3-dimensional screen printingsystem to adjust the screen holder rail separately at each corner pointin its distance to the printing substrate. The measure for theadjustment is the unloaded screen mesh, or for smaller screens also theinner edge of the screen frame. Here the screen holder displacementtoward the press bed surface is preferably plane parallel. Whenoperating with low screen tensions, it is also possible to align thescreen anti-parallel, as here due to shear forces on the screen meshduring application, the screen tension decreases with increasingdistance from the frame. Contrary to conventional methods, it has alsobeen shown that the screen fastening directly after positioning leads tounsatisfactory results. The more accurate the positioning has to be, themore prone to misplacement conventional screen clamp and positioningsystem is. In particular, all positioning systems end with themeasurement and evaluation endpoint. This is followed by clamping.However, in 3-dimensional screen printing there is no possibility ofcorrection by means of proofs, so that an identified delocalizationcould be corrected by the clamping operation. In the 3-dimensionalscreen printing system, screen positioning is performed by the detectionof at least 2 registration marks, preferably but not exclusivelyilluminated from below, if the cameras detect the mark from above, orfrom above, if the marks are detected from below. The most optimalpositioning position is on the center line of the Y axis of the layout.Other positions are also possible. Optionally in the 3-dimensionalscreen printing system a screen-specific correction value is introduced,which takes into account screen change parameters such as stretchchange, humidity change, temperature change, mass weight load change orscreen frame changes. It is practical if the registration marks are notwithin the sphere of influence of the doctor blade unit or flood path.Of course it is also possible to integrate the registration marks in theprint layout. Classic simple positioning by pen, stencils, or the likehave not been found accurate enough for 3-dimensional screen printingtechnology, nor has positioning using the screen frame. If thepositioning is performed, in the mother frame structure for the flatscreen and round screen, the screen is fixed in the mother frame and themother frame preferably but not exclusively is positioned and fixed attwo corner points and a middle axis manually, pneumatically,hydraulically, or by motor. The position deviation arising duringfixation is detected, the mother frame released and newly positioned,and corrected by the registered position deviation of the firstfixation. Then comes the second fixation. In some cases this processmust be carried out several times in order to achieve positioning of thescreen in the μm range. It has been shown that conventional screenpositioning with camera support have long evaluation times for thisrequired precision—at times lasting for hours—and do not detect,evaluate, or correct position changes occurring after the positioning.Approaches are analogous for the solid frame structure for flat screensand round screens.

Since basically in the three-dimensional screen printing method with3-dimensional screen printing system, one proceeds from the fact thatthe application axes run plane parallel to the press bed surface, thepress bed surface or for prints in progress the already printed objectsurface, is the reference surface for screen positioning, both with oneobject structure and with several object structures. If the positioningon the other hand is manual or semiautomatic, for the detection of thereference mark position, a large projection of the reference mark imageror imagers is produced, and the screen position is set by means ofassistive marks or required reference marks on the projection surfacemanually or automatically. The adjustment of the screen axes isimplemented by means of adjustment elements by motor, pneumatic, orhydraulic systems or by numerical preset values manually orsemi-automatically or automatically.

FIG. 3 shows the adjustment positions of the screen position for planeparallel orientation of the screen to press bed number 7; the adjustmentpositions of the screens for the layout orientation are shown in number8. The screen frame is marked 9, and actual layout in the screen mesh,for example for a flat screen, 10. Analogous positions for the roundscreen.

FIG. 4 represents the adjustment scheme of the doctor blade unit path.Number 16 indicates the blade beam to which the blade is fixed; 18 theblade holder fixture with adjusting pivot axes; and number 17 shows thedoctor blade. Number 22 Indicates the position-stable lift-triggeringmechanics, hydraulics, pneumatics, or motor system, and number 20 thesliding lift-triggering mechanics, hydraulics, pneumatics, or motorsystem, with displacement 15 in Y-axis direction. The blade holderfixture is rotatable in position 11, but not displaceable, andoppositely displaceable in the Y-axis direction 14 and swiveling on thecircular segment path 12. Attached to the fixed-position blade holderbar 13 is the actual blade 17, secured against rotation anddisplacement, even when loaded by the changing doctor blade unitpressure during the printing phase, in which the blade also rests on theprinting substrate and in further printing rests only on the alreadyprinted object. Not shown is the left- and right-side height-adjustablestop or the associated measurement devices. This adjustability, unusualfor doctor blade units, is based on the negative results of conventionaldoctor blade units, such as doctor blade units with doctor blade unitpressure balance, usually pneumatic, with doctor blade unit pressureadjustment, usually with a fast electronic pressure controller or simplepiston-rod controlled cylinders for doctor blade unit pressure anddoctor blade unit stroke with end-position damping plates. It is acommon feature of conventional systems that they react, that is, takeaction after onset of an event. In the 3-dimensional screen printingsystem, the blade solely because of the repositioning capacity over upto some thousand printings must rest always parallel to the screen mesh,lie on this to the left and right equally on the printing substrate oron the already present object, and be held over the complete objectcovering blade path at a constant height, without changing the pressprove values, associated also with a constancy in the angling of theblade edge. The same applies to the flood bar. Contrary to the prior artfor the 3-dimensional screen printing system, a speed influence of thelift-triggering mechanics, pneumatics, or motor systems has provenuseful, but not their end stop behavior. Here in the 3-dimensionalscreen printing system, throttling and damping is used, but not to theend; the doctor blade receiver itself however is placed on one or morefixed adjustable non-buffered stops and pressed in such a way thatduring the printing process, no height position change or evasivemovement can take place. Flood and printing doctor blade units can bedetected by controls or measurement systems independently of one anotheror controlled jointly. Here the form arrangement of the doctor bladeunit and flood bar for separate control, for mass-limiting control, orfor closed flooding between flood bar and doctor blade unit in the3-dimensional printing system must be implemented. Depending on theformula material used, there is also the possibility to perform theflooding immediately before printing, so that the screen mesh is notmass-loaded in the printing interim time.

In the 3-dimensional screen printing system there are correction optionsfor all axial positions in the form of differential preferences andsettings from the ideal position. This is necessary for example inlong-term printing if the mass is concentrated in the screen angledirection, or the screen mesh of the screen tool on the lift-off pathdeviates more in one direction than should be the case for the otherscreens in structure and/or screen change.

In conclusion, for the 3-dimensional screen printing system it should benoted that due to the demand for long-acting positional certainty andpositional certainty even in the first printing, using the bearingcombination floating bearing-fixed bearing leads to large variations inposition, certainly in the millimeter range, which owing to theresulting position and application thickness changes can lead only tomoderately accurate object dimensions, or due to the accumulation ofgenerated application thickness differences, often lead to printcancellation. By contrast, the bearing combination of fixedbearing-fixed bearing, in particular due to the controlled frameworkconditions, has proven optimal for a displacement-free and heightconstant object printing on a 3-dimensional screen printing system.

For the precision of a 3-dimensional printing system it is of decisiveimportance that, contrary to conventional technologies with onereference position beyond the system lifespan, this is not sufficientfor accuracies in the μm range of a 3-dimensional screen printingsystem. Inevitable wear of the guides, the drives, and the moving partsis here compensated by the fact that with every print start of a newprint cycle for the production of objects in the 3-dimensional screenprinting method, a new reference point is always determined, from whichthe respective new printing process is started for a 3-dimensionalprinted object. This ensures in the 3-dimensional screen printing systemthat only the wear that occurs during a single production run can affectthe precision of the print result. With a determination of the referencepoint for each manufacturing process, the cycle of repair andmaintenance or failure of the 3-dimensional printing system forexceeding tolerance warnings or limits is widened significantly with nonegative effect on the printed object.

The three-dimensional screen printing system enables the use the3-dimensional screen printing technology for the production and use ofobjects and in accordance with FIG. 1 combines the system components ofthe printing station, FIG. 1 , No. 2; upper printing mechanism, FIG. 1 ,No. 1; one or more press beds. FIG. 1 , Nos. 3 and 4; one or more curingstations FIG. 1 , Nos. 5 and 6 such that per press bed one or severalprinting exploits can be printed successively on the press bed, andsubsequently are cured jointly and at the same time. During the curingof the first press bed, the second and possibly further press beds areprinted and then cured. Following the curing of the printed body layer,for the following print layer the lift-off adjustment is made by theheight of the previously printed printing layer. The 3-dimensionalscreen printing system has in its precision capacity a number of specialsetting and functional elements, which through special bed structure,height adjustments, positioning system methods, a specially conceivedand executed blade and flood method for the 3-dimensional screenprinting system, and a flexibly equippable integrated curing system,increases the efficiency of the 3-dimensional screening printing processby at least 10% with respect to adapted conventional flat bed screenprinting machines from research and development of the 3-dimensionalscreen printing process, and at the same time, along with layout changesin the body layers, allows 3-dimensional precision printings. Objectsproduced with the 3-dimensional system technology include 3-dimensionalobjects made of ceramic, metal, glass, plastic, organic or inorganicmaterials, biological materials, or mixtures thereof, and can beproduced and used with or without a 3-dimensional structure.

LIST OF ABBREVIATIONS USED IN THE INVENTION DESCRIPTION

Z=null position of the press bed; A=lift-off; H=application thickness ofa printing

Σ=sum; f(x)=function; N=quantity of printing exploits; X=transportdirection

Y=ordinate axis; Δ=delta; Fig.=Figure; Nr=number

What is claimed:
 1. A system for the production of three-dimensionalscreen-printed articles, comprising: a press bed comprising a platehaving one or printing exploits; and a printing screen, by means ofwhich at least one printing exploit is printable several times; whereinafter each printing layer a value of a lift-off is increased by a valueof an application thickness of a previous printing layer, and whereinafter printing on the press bed with one or more exploits or on aplurality of press beds, each with one or more exploits, the value ofthe lift-off is increased between 0.2 μm and 250 μm before a subsequentprinting of a next height-building printing layer is carried out.
 2. Thesystem for the production of three-dimensional screen-printed articlesaccording to claim 1, wherein the plate with the one or more printingexploits is movable into a curing system.
 3. The system for theproduction of three-dimensional screen-printed articles according toclaim 1, wherein the system has at least two curing systems from whichthe press bed can be loaded with the plates with one or more printingexploits.
 4. The system for the production of three-dimensionalscreen-printed articles of claim 1, wherein the system is adapted toincrease the value of the lift-off by the value of the applicationthickness of a performed printing before a subsequent printing processthat raises a body of the respective exploit is carried out.
 5. Thesystem for the production of three-dimensional screen-printed articlesaccording to claim 1, further comprising a doctor blade and a flood bar,wherein at least the printing screen, the doctor blade, and the floodbar are adapted to be raised by the value of the application thickness.6. The system for the production of three-dimensional screen-printedarticles according to claim 1, wherein the press bed is adapted to belowered by the value of the application thickness.
 7. The system for theproduction of three-dimensional screen-printed articles according toclaim 1, wherein a curing system for curing of individual body layers isequipped with a curing triggering irradiation unit in which multipleones of the printing exploits can be exposed to curing simultaneously.8. The system for the production of three-dimensional screen-printedarticles according to claim 7, wherein the irradiation unit comprisesdifferent radiation sources.
 9. The system for the production ofthree-dimensional screen-printed articles according to claim 1, furthercomprising: a printing station comprising one or more holders forprinting screens, one or more doctor blade holders, one or more floodbar holders, and at least two systems to detect, analyze, and controlregistration marks, and an upper printing mechanism, which carries outthe printing, is adapted to be aligned, displaced, rotated, or replaced,with respect to a position of an object located on the press bed, asecond or more upper printing mechanism(s) before and during printing,so that in addition to one material and one layout orientation, alsoseveral materials in one or more layout orientations, or alternativelycounter to the previous printing, can be printed in an offset, rotated,or displaced manner.
 10. The system for the production ofthree-dimensional screen-printed articles according to claim 1, furthercomprising a press bed drive, a printing station, an upper printingmechanism, a lifting device for the upper printing mechanism or alowering device for the press bed, a curing system, a control system, ameasurement and control device for the press bed position, screenposition, upper printing mechanism position, as well as doctor blade andflood bar position and path, and control devices for the lift-offposition, lift amount, doctor blade and flood bar position and path,curing parameters and cycle time optimization, on one or more press bedsin one or more exploits per press bed.
 11. The system for the productionof three-dimensional screen-printed articles according to claim 1,further comprising a centrally arranged one or more lift drives andguide columns, wherein the lift drive and guide columns are arrangedsuch that (1) there is load transfer via the guide columns, (2) the liftdrives are present on each guide column with load transfer via the guidecolumns, (3) the lift drives are present next to each guide column withload transfer through the lift drive, (4) the lift drives are presentnext to each guide column with a weight-relieving device at least duringthe lifting process.
 12. The system for the production ofthree-dimensional screen-printed articles according to claim 1, thepress bed comprises an upper printing mechanism comprising a screenholder adjustable in all axial points, and adapted to orient the printscreen contained therein plane parallel or parallel with correctionvalues with respect to the print bed or a body surface, the screenholder further comprising more than one screen positioning element bywhich the screen may be oriented, and the upper printing mechanismfurther comprises one or more cameras and illumination devices formeasurement of the position of the screen.
 13. The system for theproduction of three-dimensional screen-printed articles according toclaim 1, further comprising a print flood bar configured to shiftbetween open and closed positions, and a printing doctor blade, whereinthe printing doctor blade and the print flood bar are arranged such thata lower edge of the printing doctor blade is placed plane-parallel ontothe printing screen at a pre-settable position on a left or right sideat the same time, the doctor blade edge presses the printing screen ontoa print substrate or onto already printed layers of an object, thedoctor blade orientation at an application point on the screen mesh andthe application region on the print substrate or the already printedlayers as well as the proof during the printing process are alwaysparallel, without screen tension differences, layout densitydifferences, mass friction resistances, or other subordinate influentialparameters allowing a change in position of the printing doctor bladeedge and optionally the flood bar.
 14. A method for the production ofthree-dimensional screen-printed articles, comprising the steps of:providing a press bed comprising a plate having one or printingexploits; and a printing screen, by means of which at least one printingexploit is printed several times; wherein after each printing layer avalue of a lift-off is increased by a value of an application thicknessof a previous printing layer, and wherein after printing on the pressbed with one or more exploits or on a plurality of press beds, each withone or more exploits, the value of the lift-off is increased between 0.2μm and 250 μm before a subsequent printing of a next height-buildingprinting layer is carried out.